1. Field of the Invention
The present invention relates to a supporting structure, more particularly to a supporting structure having function of rod-linkage latching, a rod-linkage mechanism is latched or released by a rod-linkage latching device so as to suppress or release an elastic force of a torsion spring disposed between a connecting unit and a base seat.
2. Description of Related Art
Flat panel monitors, e.g. liquid crystal monitors, liquid crystal displays or plasma TVs, have advantages of light in weight, thin and no radiation, etc., and are used to replace conventional CRT monitors. When viewing, the liquid crystal and the plasma monitors have limitations of viewing angles, so a structure of rotation shaft is often provided between the an above mentioned monitor and a base seat for providing a function of adjusting elevation angle of the monitor, with respect to the base seat.
But the described fashion can not provide functions of ascent/descent and forward/backward movement to the flat panel monitors. Auxiliary connecting units disposed in parallel are therefore invented, and two end sections of the two auxiliary connecting units are respectively connected between a main hinge at an upper portion of a connecting unit and a base seat hinge at the lower portion of the connecting unit. For instance, in the patent, CN 1244852C, granted by China government on Mar. 8, 2006 (corresponding to the U.S. Pat. No. 6,822,857) titled in “Monitor improved in a tilting structure”, the elements numbered as 100 and 110 shown in FIG. 5 of the patent are a pair of auxiliary connecting units parallel to each other. And a four-rod linkage mechanism is formed by the pair of auxiliary connecting units, a main hinge and a base seat hinge of the connecting unit, so the rotation movement of the connecting unit, with respect to the base seat unit, is converted into a tilt movement of a monitor main body by the auxiliary connecting units. In other words, in order to adjust the height of the monitor main body, while the monitor main body is tilted by the connecting unit in an up/down direction, only a second and a third friction springs (sleeve tubes) connected to a main supporting rack rotate around a third and a fourth hinge pins, so when moving, the angle of the monitor main body is remained.
At least a torsion spring is provided between the connecting unit and the base seat hinge of the base seat provided by the above mentioned patent, and two ends of the torsion spring respectively lean against the base seat hinge and the connecting unit, so a reaction force with the direction opposite to the forward rotation of the monitor main body connected to the connecting unit is formed. Therefore, with providing of the torsion springs, the connecting unit has a tilt angle, with respect to the base seat. But during hanging or packaging and conveying the supporting structure, the tilting status of the connecting unit would result in occupying extra space; if the connecting unit is forced to rotate toward the base seat and being positioned, the elastic forces of the torsion springs are needed to be overcome. So how to provide a latching mechanism between the connecting unit and the base seat to allow the connecting unit rotates toward the base seat to a positioning location so a latch is automatically formed and to further suppress the reaction forces of the torsion springs is still an issue needed to be solved.